Nine episodes of subclinical scurvy were investigated. Diagnosis was based on histological examination of the femoro-tibial articulation. Ascorbic acid is necessary for connective tissue and matrix formation. Therefore, osteoid trabeculae formation in the metaphysis of the tibia was used as an index of ascorbic acid. In guinea pigs with sub clinical scurvy, there was a marked decrease in osteoid trabeculae formation without classical lesions of overt scurvy. Clinical histories of all episodes revealed poor food management practices. These included storage of food at abnormally high temperatures, improper formulation by the manufacturer and abnormally long periods of storage. Overt scurvy did develop as a sequel to subacute scurvy when adequate corrective measures were not taken. Purified ascorbic acid was given to the survivors and they recovered. We believe subclinical scurvy is a potential cause for major losses in guinea pig colonies, and that whenever significant losses are encountered without significant gross lesions, subclinical scurvy should be considered in the differential diagnosis.